METHOD FOR PRODUCING MOLDED BODY AND MOLDED BODY PRODUCING APPARATUS

Description

The present application is based on, and claims priority from JP Application Serial Number 2024-218807, filed Dec. 13, 2024, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a method for producing a molded body and a molded body producing apparatus.

2. Related Art

For example, JP-A-2024-113315 discloses an apparatus for producing a sheet from fibers.

However, sufficient study has not been made regarding manufacturing a product using a sheet produced by the method described in JP-A-2024-113315.

SUMMARY

A method for producing a molded body according to an application example of the present disclosure includes accumulating a material including fibers to form an accumulated material having a first portion and a second portion that is thinner than the first portion, molding a first molded body by bonding the fibers of the accumulated material to each other, and bending the first molded body at the second portion to generate a second molded body.

A molded body producing apparatus according to an application example of the present disclosure includes an accumulation section including an accumulation member on which a material including fibers is accumulated, the accumulation section being configured to generate an accumulated material of the material, a molding section configured to mold a first molded body by bonding fibers of the accumulated material to each other, a bending section configured to bend the first molded body to generate a second molded body, and a control section configured to control an operation of the accumulation section, in which the control section controls the operation of the accumulation section to generate the accumulated material having a first portion and a second portion that is thinner than the first portion, and the bending section generates the second molded body by bending at the second portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a configuration diagram showing an outline of a molded body producing apparatus according to a first embodiment of the present disclosure.

FIG. 2 is a flowchart of a method for producing a molded body according to the first embodiment of the present disclosure.

FIG. 3 is a block diagram of the molded body producing apparatus shown in FIG. 1.

FIG. 4 is a sectional view of an accumulated material generated by an accumulation section shown in FIG. 1.

FIG. 5 is a sectional view showing an accumulated sheet, a laminate, and a first molded body.

FIG. 6 is a time chart for explaining changes over time in a thickness of the accumulated material and a moving speed of the accumulated material.

FIG. 7 is a sectional view of a laminate generated by a molded body producing apparatus according to a second embodiment of the present disclosure.

FIG. 8 is a sectional view of a laminate generated by a molded body producing apparatus according to a third embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a method for producing a molded body and a molded body producing apparatus according to the present disclosure will be described in detail based on preferred embodiments shown in the accompanying drawings.

First Embodiment

FIG. 1 is a configuration diagram showing an outline of a molded body producing apparatus according to a first embodiment of the present disclosure. FIG. 2 is a flowchart of a method for producing a molded body according to the first embodiment of the present disclosure. FIG. 3 is a block diagram of the molded body producing apparatus shown in FIG. 1. FIG. 4 is a sectional view of an accumulated material generated by an accumulation section shown in FIG. 1. FIG. 5 is a sectional view showing an accumulated sheet, a laminate, and a first molded body. FIG. 6 is a time chart for explaining changes over time in a thickness of the accumulated material and a moving speed of the accumulated material.

Hereinafter, an upper side in FIGS. 1, 4, and 5 (the same applies to FIGS. 7 and 8) may be referred to as “upper” or “upward”, and the lower side may be referred to as “lower” or “downward”. In addition, FIG. 1 is a schematic configuration diagram, and a positional relationship, a direction, a size, and the like of each section of the molded body producing apparatus 100 are not limited to those shown in the drawing. In FIG. 1, a direction in which a material or a molded body is transported is also referred to as a transport direction.

Molded Body Producing Apparatus 100

The molded body producing apparatus 100 shown in FIGS. 1 and 3 is an apparatus for executing a method for producing a molded body of the present disclosure, and is an apparatus for molding a material M1 including fibers and producing a second molded body S4 as a molded body. The molded body producing apparatus 100 includes an accumulation section 1, a cutting section 3, a molding section 4, a bending section 5, and a control device 7. In addition, as shown in FIG. 2, the method for producing a molded body includes an accumulation step, a cutting step, a molding step, and a bending step. In the present embodiment, a case where a book cover is manufactured using the second molded body S4 will be described as an example. However, the present disclosure is not limited thereto, and a final product manufactured from the second molded body S4 may be various articles such as a mask, gloves, socks, a handbag, a business card case, and slippers. Further, the second molded body S4 may be a final product such as a mask, gloves, socks, a handbag, a business card case, and slippers. Hereinafter, each section of the molded body producing apparatus 100 and each step of the method for producing a molded body will be described in detail.

Material M1

First, a material M1 will be described. The material M1 includes fibers F and a binder P that binds the fibers F to each other. The binder P may be omitted.

The fibers F are not particularly limited, and examples thereof include various natural fibers and various chemical fibers.

The average fiber length of the fibers F is not particularly limited, but is, for example, preferably 0.1 mm or more and 10 mm or less, and more preferably 1 mm or more and 5 mm or less. Thus, the strength of the second molded body S4 can be more reliably increased, and processing such as a cutting step and a bending step described below can be more easily performed.

From the same viewpoint, the average width (average diameter) of the fibers F is not particularly limited, but is, for example, preferably 0.5 μm or more and 200 μm or less, and more preferably 1.0 μm or more and 100 μm or less.

From the same viewpoint, the content of the fibers F in the material M1 is not particularly limited, but is, for example, preferably 20% by weight or more and 99% by weight or less, and more preferably 50% by weight or more and 90% by weight or less.

Examples of the binder P include thermoplastic resins such as various polyolefins, acrylic resins, polyvinyl chloride, polyester, and polyamide, various thermoplastic elastomers, and natural components such as starch, dextrin, glycogen, amylose, hyaluronic acid, kudzu, konjac, potato starch, etherified starch, esterified starch, natural gum paste, fiber-derived paste, seaweeds, and animal protein, and one kind selected therefrom or a combination of two or more kinds may be used.

The binder P is in the form of particles or fibers.

When the binder P is in the form of particles, an average particle diameter (on a volume basis) thereof is not particularly limited, but is, for example, preferably 0.5 μm or more and 200 μm or less, and more preferably 1.0 μm or more and 100 μm or less. Thus, the strength of the second molded body S4 can be more reliably increased, and processing such as a cutting step and a bending step described below can be more easily performed.

From the same viewpoint, when the binder P is in the form of fibrous, the average fiber length of the binder P is not particularly limited, but is, for example, preferably 0.1 mm or more and 10 mm or less, and more preferably 1 mm or more and 10 mm or less.

From the same viewpoint, when the binder P is in the form of fibrous, the average width (average diameter) of the binder P is not particularly limited, but is, for example, preferably 0.5 μm or more and 200 μm or less, and more preferably 1.0 μm or more and 100 μm or less.

From the same viewpoint, the content of the binder P in the material M1 is not particularly limited, but is, for example, preferably 1% by weight or more and 80% by weight or less, and more preferably 10% by weight or more and 50% by weight or less.

The material M1 may include components other than the fibers F and the binder P. As the other components, examples include a coloring agent for coloring the fibers F, an aggregation inhibitor for suppressing aggregation of the fibers F, and a flame retardant for making the fibers F and the like less flammable, and one kind or a combination of a plurality of kinds may be used. In addition, if the fibers F themselves dissolve or soften and the fibers F are bonded to each other, the binder P may not be included in addition to the fibers F.

When the material M1 includes other components, the content of other components in the material M1 is not particularly limited, but is, for example, preferably 0.1% by weight or more and 10% by weight or less, and more preferably 0.5% by weight or more and 5% by weight or less. Accordingly, the effect of blending the other components is achieved, the amounts of the fibers F and the binder P can be sufficiently ensured, and the strength of the second molded body S4 can be effectively increased.

Accumulation Section 1 and Accumulation Step

As shown in FIG. 1, the accumulation section 1 is a portion that performs an accumulation step of generating an accumulated material M2 by moving a mesh belt 12 while accumulating the material M1 on the mesh belt 12 which is an accumulation member. As shown in FIG. 1, the accumulation section 1 includes a dispersing section 11, the mesh belt 12, a suction section 13, a sheet supply section 14, and a motor 82 as a moving section.

The dispersing section 11 disentangles the fibers F entangled with each other in the material M1 and discharges the fibers F. The dispersing section 11 includes a drum 111 that introduces and discharges the material M1 and a housing 112 that houses the drum 111.

The drum 111 is formed of a cylindrical mesh body, and is a sieve that rotates around a central axis thereof. As the drum 111 rotates, the fibers F and the like smaller than the mesh openings in the material M1 can pass through the drum 111. At this time, the material M1 is disentangled and discharged together with air. That is, the drum 111 functions as a discharge section that discharges the material M1 including the fibers F.

The drum 111 is coupled to a motor 81 as a drive source, and is rotated by a rotational force output from the motor 81. As shown in FIG. 3, the motor 81 is electrically coupled to the control device 7, and the operation of the motor 81 is controlled.

Further, the material M1 discharged by the drum 111 falls while being dispersed in the air, and is directed toward the mesh belt 12 positioned below the drum 111.

A material supply section (not shown) is coupled to the drum 111. As the material supply section, examples include a configuration having a raw material supply section, a coarse crushing section, a defibrating section, and a mixing section, and the like in a sheet producing apparatus described in JP-A-2024-113315, or a configuration that supplies the material M1 in a cartridge manner.

The mesh belt 12 is the accumulation member and is formed of an endless belt in the configuration shown in the drawing. A sheet S is supplied to the mesh belt 12 from the sheet supply section 14, which will be described later, and the material M1 dispersed and discharged by the dispersing section 11 is accumulated on the sheet S, and the accumulated material M2 is generated. The mesh belt 12 is wound around four tension rollers 121. By the rotational drive of the tension roller 121, the accumulated material M2 on the mesh belt 12 is transported downstream.

In the shown configuration, the mesh belt 12, which is an endless belt, is used as an example of the accumulation member. However, the present disclosure is not limited thereto, and for example, a configuration using a plate-shaped mesh member may also be adopted.

At least one of the four tension rollers 121 is coupled to the motor 82 (moving section) as a drive source, and is rotated by the rotational force output from the motor 82. Of the four tension rollers 121, the tension roller 121 that is not coupled to the motor 82 functions as a driven roller. As shown in FIG. 3, the motor 82 is electrically coupled to the control device 7, and the operation of the motor 82 is controlled.

The suction section 13 is a suction mechanism that sucks air from below the mesh belt 12. Thus, the material M1 can be sucked onto the mesh belt 12. Accordingly, accumulation of the material M1 onto the sheet S is promoted.

A tube 131 is coupled to the suction section 13. In addition, a blower 132 is installed in the middle of the tube 131. By the operation of the blower 132, a suction force can be generated in the suction section 13. The blower 132 is electrically coupled to the control device 7, and the operation thereof is controlled.

The sheet supply section 14 includes a supply roller 141 and has a function of feeding the sheet S by rotation of the supply roller 141. The sheet S fed by the supply roller 141 is supplied onto the mesh belt 12. Then, the accumulated material M2 is generated on the sheet S. Hereinafter, the sheet S and the accumulated material M2 accumulated on the sheet S are collectively referred to as an “accumulated sheet S1”. However, when the accumulated material M2 is formed on the mesh belt 12 without using the sheet S or the sheet S is peeled off after the accumulated material M2 is formed, only the accumulated material M2 may be referred to as the accumulated sheet S1.

The sheet supply section 14 may be omitted. In this case, the material M1 is accumulated directly on the mesh belt 12.

The supply roller 141 is coupled to a motor 83 and is rotated by a rotational force output from the motor 83. As shown in FIG. 3, the motor 83 is electrically coupled to the control device 7, and the operation of the motor 83 is controlled.

The sheet S has air permeability and is formed of a woven fabric, a nonwoven fabric, or the like. Examples of fibers constituting the sheet S include those exemplified for the fibers F described above. By supplying such a sheet S, the strength of the second molded body S4 can be increased more effectively, and processing such as a cutting step and a bending step, which will be described later, can be carried out more easily.

As shown in FIG. 5, an average thickness T_S of the sheet S is not particularly limited, but is preferably 0.01 mm or more and 20 mm or less, and more preferably 0.1 mm or more and 2 mm or less. Thus, the strength of the second molded body S4 can be more reliably increased, and processing such as a cutting step and a bending step described below can be more easily performed.

From the same viewpoint, a density ρ_M1 of the material M1 of the accumulated material M2 is not particularly limited, but is preferably 0.01 g/cm³ or more and 2.0 g/cm³ or less, and more preferably 0.1 g/cm³ or more and 1.0 g/cm³ or less.

From the same viewpoint, as shown in FIG. 5, an average thickness T_M2 of the accumulated material M2 (an average thickness of a first portion 21 described later) is not particularly limited, but is preferably 1 mm or more and 100 mm or less, and more preferably 1.5 mm or more and 50 mm or less.

From the same viewpoint, an average thickness T_S1 of the accumulated sheet S1 (the average thickness of the portion having the first portion 21 described later) is not particularly limited, but is preferably 1.1 mm or more and 120 mm or less, and more preferably 1.3 mm or more and 60 mm or less.

Cutting Section 3 and Cutting Step

As shown in FIG. 1, the cutting section 3 performs the cutting step and cuts the accumulated sheet S1 into a desired size. The cutting section 3 includes a pair of cutting blades 31 provided downstream of the accumulation section 1. The cutting blades 31 are arranged one above the other across a transport path of the accumulated sheet S1. The cutting blades 31 are arranged such that cutting edges face each other and are configured to be movable toward and away from each other. When the cutting edges of the cutting blades 31 come into contact with each other, the accumulated sheet S1 passing between the cutting blades 31 is cut. Further, the length of the accumulated sheets S1 can be adjusted by adjusting the timing at which the cutting blades 31 are moved toward and away from each other. In the following, the accumulated sheet S1 cut to a predetermined length will be referred to as an “accumulated sheet S2”.

The cutting blades 31 are coupled to a motor 84 as a drive source and move toward and away from each other by a force output from the motor 84. As shown in FIG. 3, the motor 84 is electrically coupled to the control device 7, and the operation of the motor 84 is controlled.

A pair of transport rollers 32 are provided downstream of the cutting blades 31. The path of transport rollers 32 are arranged one above the other across the transport path of the accumulated sheet S2. When the transport rollers 32 rotates while holding the cut accumulated sheets S2 therebetween, the accumulated sheet S2 can be transported downstream, that is, to the molding section 4.

The transport rollers 32 are coupled to a drive source (not shown) and are rotated by a rotational force output from the drive source. The drive source is electrically coupled to the control device 7, and the operation thereof is controlled.

The cutting section 3 is not limited to the above-described configuration, and may be configured to have a cutting roller in which a blade is formed on an outer peripheral portion of the roller, instead of the cutting blade 31.

Although not shown, the cutting section 3 may have a cutting blade that cuts both edge portions in a widthwise direction of the accumulated sheet S1 or the accumulated sheet S2.

Further, the cutting section 3 may be omitted. In this case, it is preferable that, prior to molding in a molding section 4 described later, the accumulated sheet S1 is bent and stacked in the thickness direction.

Molding Section 4 and Molding Step

As shown in FIG. 1, the molding section 4 has a pressing section 41, and is a step of molding a first molded body S3 by compressing the accumulated sheets S2 by heating and pressing the accumulated sheets S2 using the pressing section 41. In the present embodiment, after a plurality of accumulated sheets S2 are stacked to form a laminate S21, the laminate S21 is heated and pressed. That is, the accumulated materials M2 are stacked and each of the accumulated material M2 is pressed.

The number of accumulated sheets S2 in the laminate S21 is not particularly limited, but is preferably 1 or more and 20 or less, and more preferably 1 or more and 10 or less. Accordingly, the strength of the first molded body S3, which will be described later, can be increased more effectively and the adjacent stacked accumulated sheets S2 can be favorably bonded.

In the present embodiment, the plurality of accumulated sheets S2 are stacked such that, in the accumulated sheets S2 adjacent to each other in the thickness direction, one sheet S and the other accumulated material M2 are in contact with each other. However, the present disclosure is not limited to this configuration, and one sheet S and the other sheet S may be stacked so as to be in contact with each other, one accumulated material M2 and the other accumulated material M2 may be stacked so as to be in contact with each other, or a stacking order in which such arrangements and the shown arrangement are combined may be adopted.

The pressing section 41 includes a block-shaped pressing member 411 and a block-shaped pressing member 412 as a pressing mechanism. The pressing member 411 and the pressing member 412 are metal dies, but are not limited thereto and may be ceramic dies or the like. The plurality of accumulated sheets S2 are stacked and arranged on the pressing member 411. The pressing member 412 is coupled to a drive source (not shown), and is configured to be movable toward and away from the pressing member 411. When the pressing member 412 is moved toward the pressing member 411, the accumulated sheet S2 on the pressing member 411 is held between the pressing member 411 and the pressing member 412, heated and pressed, and a first molded body S3 is generated. When the above pressing is released, the accumulated sheet S2 can be arranged on the pressing member 411, or the first molded body S3 can be removed from the pressing member 411.

The pressing member 411 and the pressing member 412 are not limited to a block shape, and may be formed of, for example, a roller.

The drive source and the heat source are electrically coupled to the control device 7, and the pressing timing, the heating timing, the degree of pressing, and the degree of heating are controlled. The pressing member 411 may also be coupled to the heat source, or only the pressing member 411 may be coupled to the heat source.

When the molding section 4 applies pressure, the fibers F in each of the accumulated sheets S2 are compressed and densified, so that the first molded body S3 having a relatively high strength can be molded, and the adjacent stacked accumulated sheets S2 can be more effectively bonded to each other. The binder P in the accumulated sheet S2 can also be melted or softened and used to impregnate spaces between the fibers F by the molding section 4 applying pressure and heat. Accordingly, the strength of the first molded body S3, which will be described later, can be increased more effectively by bonding the fibers F to each other and the adjacent stacked accumulated sheets S2 can be favorably bonded.

As shown in FIG. 5, an average thickness T_S3 of one accumulated sheet S2 in the first molded body S3 is not particularly limited, but is preferably 0.5 mm or more and 90 mm or less, and more preferably 1 mm or more and 40 mm or less. By performing pressing of this degree in the molding section 4, the strength of the first molded body S3 can be more effectively increased, and processing such as a bending step described later can be performed more easily.

A density ρ_S3 of the material M1 in one accumulated sheet S2 of the first molded body S3 (a density of the material M1 in a high-density portion 21A described later) is not particularly limited, but is preferably 0.03 g/cm³ or more and 4.0 g/cm³ or less, and more preferably 0.2 g/cm³ or more and 2.5 g/cm³ or less. By performing pressing of this degree in the molding section 4, the strength of the first molded body S3 can be more effectively increased.

A ratio ρ_S2/ρ_S3 between a density ρ_S2 (g/cm³) of material M1 in the accumulated sheet S2 and a density ρ_S3 (g/cm³) of material M1 in one accumulated sheet S2 of the first molded body S3 is not particularly limited, but is preferably 0.2 or more and 0.8 or less, and more preferably 0.3 or more and 0.7 or less. By performing pressing of this degree in the molding section 4, the strength of the first molded body S3 can be more effectively increased, and processing such as a bending step described later can be performed more easily.

A heating temperature in the molding section 4 is not particularly limited, and is, for example, preferably 40° C. or more and 200° C. or less, and more preferably 130° C. or more and 190° C. or less. Thus, the binder P can be more effectively melted or softened, and the fibers F can be more firmly bonded to each other. Therefore, the strength of the first molded body S3 can be more effectively increased.

The time for which the molding section 4 performs heating and pressing is not particularly limited, and is, for example, preferably 1 second or more and 60 seconds or less, and more preferably 2 seconds or more and 45 seconds or less. Thus, the binder P can be melted or softened more effectively.

A cooling step may be performed after the molding step. A temperature after cooling may be any temperature at which the binder P solidifies, and is preferably, for example, room temperature. The cooling step is not particularly limited, but may have a configuration in which a cooling block or a cooling roller is brought into contact with both surfaces of the first molded body S3, may have a configuration in which cold air is blown to the first molded body S3, or may have a configuration in which the first molded body S3 is arranged in a chamber and heat is dissipated from the first molded body S3. In addition, a configuration may be adopted in which heating by the pressing member 411 and the pressing member 412 is released, and the first molded body S3 is cooled by keeping the pressing member 411 and the pressing member 412 in contact with the first molded body S3 until temperatures of the pressing member 411 and the pressing member 412 decrease.

By performing such a cooling step, the binder P of the first molded body S3 can be solidified and the bonding between the fibers F can be strengthened.

Bending Section 5 and Bending Step

The bending section 5 is a portion that performs a bending step of bending the first molded body S3 and generating the second molded body S4. As the bending section 5, for example, a configuration in which the first molded body S3 is bent by sharply changing the transport direction while transporting the first molded body S3 by a roller, a configuration in which the first molded body S3 is bent by using a robot arm, or the like can be employed.

A lower limit of a bending angle in the bending step is preferably 1°, and more preferably 10°. An upper limit of the bending angle in the bending step is preferably 180°. Thus, for example, a product value as a notebook cover can be more effectively increased.

The “bending angle” is a numerical value indicating a degree of bending, with 0°defined as the sheet-shaped first molded body S3 before bending, in a natural state in which no external force is applied to the second molded body S4 after completion of the bending step. For example, FIG. 1 shows a state of being bent at a bending angle of 180°.

Through such a bending step, the first molded body S3 having a bending section, that is, the second molded body S4 can be generated.

As will be described later, by bending the portion of the first molded body S3 corresponding to the second portion 22 in the bending step, the bending step can be performed easily and accurately.

If necessary, cutting, sewing, printing, or the like may be performed before or after bending in the bending step.

Control Device 7

Each section included in the molded body producing apparatus 100 is electrically coupled to the control device 7. The operation of each of these sections is controlled by the control device 7.

As shown in FIG. 3, the control device 7 includes a control section 71, a storage section 72, and a communication section 73.

The control section 71 has at least one processor and executes various programs stored in the storage section 72. As the processor, for example, a central processing unit (CPU) can be used. In addition, the control section 71 has various functions such as a function of controlling the driving of each section of the apparatus related to the producing of the molded body. Specifically, the control section 71 controls energization conditions to the motors 81 to 84, controls the supply speed of the sheet S, the moving speed of the mesh belt 12, and the rotation speed of the cut timing in the cutting section 3, and controls the thickness distribution of the accumulated material M2 as will be described later.

The storage section 72 stores, for example, a program for executing the method for producing a molded body of the present disclosure. The program for executing the method for producing a molded body according to the present disclosure may be stored in a storage device other than the storage section 72, for example, a storage device of a server, an external storage device which is attachable to and detachable from the control device 7, or the like.

The communication section 73 is constituted by, for example, an I/O interface, and communicates with each section of the molded body producing apparatus 100. Further, the communication section 73 has a function of communicating with, for example, a computer or a server (not shown) via a network.

The control device 7 may be built in the molded body producing apparatus 100, or may be provided in an external device such as an external computer. In addition, for example, the control section 71 and the storage section 72 may be integrated and configured as one unit, the control section 71 may be built in the molded body producing apparatus 100 and the storage section 72 may be provided in an external device such as an external computer, or the storage section 72 may be built in the molded body producing apparatus 100 and the control section 71 may be provided in an external device such as an external computer.

Here, by adjusting the moving speed of the mesh belt 12 in the above-described accumulation step, a portion serving as a starting point of bending in the bending step is formed in the accumulated material M2. That is, in the accumulation step, by adjusting the moving speed of the mesh belt 12, the first portion 21 and the second portion 22, which is thinner than the first portion 21 and is a portion to be bent in the bending step, are formed. This will be described in detail below.

The moving speed of the mesh belt 12 refers to the moving speed of an upper surface of the mesh belt 12, and is the same as the transport speed of the accumulated material M2.

In the present embodiment, the first portion 21 and the second portion 22 are formed in the accumulated material M2 by synchronously adjusting the supply speed of the sheet S together with the moving speed of the mesh belt 12. When a configuration in which the sheet S is not supplied is employed, the first portion 21 and the second portion 22 can be formed in the accumulated material M2 by adjusting only the moving speed of the mesh belt 12.

The control section 71 adjusts the energization conditions of the motor 82 and the motor 83 by reading and executing the program stored in the storage section 72. As a result, the rotational force output by the motor 82 and the motor 83 can be adjusted, and the moving speed of the mesh belt 12 and the supply speed of the sheet S can be adjusted.

When the moving speed of the mesh belt 12 and the supply speed of the sheet S are decreased, the amount of the material M1 accumulated per unit area increases, the accumulated material M2 becomes thicker, and a basis weight of the material M1 increases. On the other hand, when the moving speed of the mesh belt 12 and the supply speed of the sheet S are increased, the amount of the material M1 accumulated per unit area relatively decreases, the accumulated material M2 becomes thinner, and the basis weight of the material M1 decreases.

The control section 71 adjusts the energization conditions of the motor 82 and the motor 83 to generate the accumulated material M2 having a distribution of thicknesses as shown in FIGS. 4 and 5. The accumulated material M2 has the first portion 21 and the second portion 22. Although the thickness of the accumulated material M2 in practice varies, it is shown as a uniform thickness in FIG. 1 for convenience.

The first portion 21 is a constant-thickness portion and is the thickest portion of the accumulated material M2. The average thickness of the first portion 21 is the above-described average thickness T_S1.

The second portion 22 is thinner than the first portion 21 and serves as a starting point of bending in the bending step. The second portion 22 has a flat portion 221 that is thinnest in thickness, an inclined portion 222 located upstream of the flat portion 221 in a moving direction of the mesh belt 12, and an inclined portion 223 located downstream of the flat portion 221 in the moving direction of the mesh belt 12. The flat portion 221, the inclined portion 222, and the inclined portion 223 extend in a depth direction in FIGS. 4 and 5, that is, over the entire area in the widthwise direction of the accumulated sheets S2.

As shown in FIG. 5, an average thickness T₂₂₁ of the flat portion 221 is not particularly limited, but is, for example, preferably 0.01 mm or more and 15 mm or less, and more preferably 0.15 mm or more and 9 mm or less. With this configuration, the strength of the first molded body S3 can be more reliably increased, and the bending in the bending step can be more easily and accurately performed.

A ratio T₂₂₁/T_M2 between the average thickness T₂₂₁ (mm) of the flat portion 221 and the average thickness T_M2 (mm) of the accumulated material M2 is not particularly limited, but is preferably 0.1 or more and 0.9 or less, and more preferably 0.2 or more and 0.8 or less. With this configuration, the strength of the second molded body S4 can be more reliably increased, and the bending in the bending step can be more easily and accurately performed.

The thickest portions of the inclined portion 222 and the inclined portion 223 have the same thickness as the first portion 21, and the thinnest portions have the same thickness as the flat portion 221. The inclined portion 222 and the inclined portion 223 have different inclination directions but have the same inclination angle.

A length L₂₂ of the second portion 22 (a length in the moving direction of the mesh belt 12) is not particularly limited, but is preferably, for example, 5 mm or more and 50 mm or less, and more preferably 10 mm or more and 30 mm or less. Thus, the bending angle can be more effectively increased, and the bending can be more easily and accurately performed.

A ratio T₂₂₁/L₂₂ between the length L₂₂ (mm) and the average thickness T₂₂₁ (mm) is not particularly limited, but is, for example, preferably 0.01 or more and 1.0 or less, and more preferably 0.1 or more and 0.5 or less. Thus, even when a thickness of the accumulated sheet S2 is relatively large, the bending angle can be more effectively increased, and the bending can be more easily and accurately performed.

The flat portion 221, the inclined portion 222, and the inclined portion 223 have the same length in the transport direction. However, the configuration is not limited to this, and the lengths of these portions may be different. In addition, the inclined portion 222 and the inclined portion 223 may have different inclination angles.

Such a second portion 22 can be formed as follows. Hereinafter, the accumulation step will be described with reference to the time chart shown in FIG. 6.

In FIG. 6, a thickness of the accumulated material M2 (directly below the dispersing section 11) and a moving speed of the accumulated material M2 are shown, a horizontal axis represents time, and a vertical axis represents a value of the speed. In FIG. 6, each value increases toward an upper side and decreases toward a lower side. In addition, although the time t0 to the time t7 are shown in chronological order, it is assumed that the dispersion amount per unit time of the material M1 from the dispersing section 11 is constant from the time t0 to the time t7 and thereafter.

From time t0 to time t2, the control section 71 controls the operations of the motor 82 and the motor 83 such that the mesh belt 12 and the supply roller 141 operate at the moving speed V1. Accordingly, a thickness of the accumulated material M2 generated between time t0 and time t2 becomes constant. This portion is the first portion 21.

From time t2 to time t3, the control section 71 controls the operations of the motor 82 and the motor 83 such that the speed is continuously increased from the moving speed V1 and becomes the moving speed V2 at the time t3. Accordingly, a thickness of the accumulated material M2 generated between time t2 and time t3 gradually decreases. This portion is the inclined portion 222.

From time t3 to time t4, the control section 71 controls the operations of the motor 82 and the motor 83 such that a moving speed becomes the moving speed V2. Accordingly, a thickness of the accumulated material M2 generated between time t3 and time t4 becomes constant. This portion is the flat portion 221.

From the time t4 to the time t5, the control section 71 controls the operations of the motor 82 and the motor 83 such that the speed is continuously decreased from the moving speed V2 and becomes the moving speed V1 at the time t5. Accordingly, a thickness of the accumulated material M2 generated between time t4 and time t5 gradually increases. This portion is the inclined portion 223.

After time t5, the same control as that from time t0 to time t2 is repeated for a predetermined time. As a result, the accumulated sheet S1 in which the second portions 22 are formed at predetermined intervals can be obtained. By controlling the operation of the motor 84 so as to cut the accumulated sheet S1 at a predetermined time interval, the accumulated sheets S2 cut to a predetermined length can be obtained. Since the second portion 22 is formed in the accumulated sheet S2, the first molded body S3 has a uniform thickness, but the density of the material M1 in the portion corresponding to the second portion 22 is lower than that of the surrounding portion (the first portion 21). That is, as shown in FIG. 5, in the first molded body S3, a high-density portion 21A corresponding to the first portion 21 and a low-density portion 22A corresponding to the second portion 22 are formed. In the bending step, the first molded body S3 can be easily and accurately bent with the low-density portion 22A as a starting point. As a result, the second molded body S4 having high quality can be easily obtained.

As described above, the method for producing a molded body includes an accumulation step of accumulating the material M1 including the fibers F on the mesh belt 12 as the accumulation member, a molding step of molding the first molded body S3 by bonding the fibers F of the accumulated material M2, and a bending step of bending the first molded body S3 to generate the second molded body S4. In the accumulation step, the first portion 21 and the second portion 22 that is thinner than the first portion 21 are formed in the accumulated material M2, and in the bending step, the first molded body S3 is bent at the second portion 22. Thus, in the bending step, the first molded body S3 can be easily and accurately bent with the portion corresponding to the second portion 22 (the low-density portion 22A) as a starting point. As a result, the second molded body S4 having high quality can be easily obtained.

In the present embodiment, the moving speed V1 of the mesh belt 12 and the moving speed V2 of the mesh belt 12 satisfy V1<V2, and the first portion 21 and the second portion 22 are formed in the accumulated material M2 by adjusting the moving speed of the mesh belt 12, but the first portion 21 and the second portion 22 may be formed in the accumulated material M2 by another method. For example, the dispersion amount of the material M1 of the dispersing section 11 may be adjusted to be smaller at a timing when the second portion 22 is formed than at a timing when the first portion 21 is formed. The accumulated material M2 may also be formed by removing fibers F in a portion to be the second portion 22 from an accumulated material having a uniform thickness, thereby forming the second portion 22. Alternatively, these methods may be combined.

Further, in the accumulation step, the material M1 is accumulated on the mesh belt 12 while moving the mesh belt 12 at the moving speed V2 to form the second portion 22 of the accumulated material M2, and the material M1 is accumulated on the mesh belt 12 while moving the mesh belt 12 at the moving speed V1 to form the first portion 21 of the accumulated material M2. Thus, the second portion 22 can be formed by simple control.

In addition, in the accumulation step, the moving speed of the mesh belt 12 is continuously changed between the moving speed V1 and the moving speed V2. That is, from time t2 to time t3, the control section 71 controls operations of the motor 82 and the motor 83 such that a moving speed is continuously increased from the moving speed V1 and becomes the moving speed V2 at time t3, and from time t4 to time t5, the control section 71 controls operations of the motor 82 and the motor 83 such that the moving speed is continuously decreased from the moving speed V2 and becomes the moving speed V1 at time t5. Thereby, it is possible to prevent the thickness from changing sharply between the first portion 21 and the second portion 22, and it is possible to further increase the strength at the boundary portion between the first portion 21 and the second portion 22.

Further, the moving speed V1 and the moving speed V2 are appropriately set according to the thickness of the first portion 21 and a thickness distribution of the second portion 22 which are intended. The thickness of the first portion 21 and the thickness distribution of the second portion 22 are set, for example, according to the bending angle in the bending step. That is, in the accumulation step, the moving speed V2 is set according to the bending angle in the bending step. Thus, a desired bending angle can be obtained in the bending step.

Further, in the molding step, the first molded body S3 is molded by pressing the laminate S21 in which the plurality of accumulated sheets S1 each having the accumulated material M2 including the first portion 21 and the second portion 22 are stacked. Accordingly, the strength of the first molded body S3 can be more effectively increased. In particular, the portion of the first molded body S3 corresponding to the second portion 22 has a low density of the material M1 and a relatively low strength. Therefore, the above-described configuration is particularly effective.

The molded body producing apparatus 100 includes the accumulation section 1 that has the mesh belt 12 as the accumulation member on which the material M1 including the fibers F is accumulated and that generates the accumulated material M2 of the material M1, a molding section 4 that molds the first molded body S3 by bonding the fibers F of the accumulated material M2, a bending section 5 that bends the first molded body S3 to generate the second molded body S4, and the control section 71 that controls the operation of the accumulation section 1. The control section 71 controls the operation of the accumulation section 1 such that the accumulated material M2 including the first portion 21 and the second portion 22 that is thinner than the first portion 21 is generated, and the bending section 5 generates the second molded body S4 by bending at the second portion 22. Thus, in the bending step, the first molded body S3 can be easily and accurately bent with the portion corresponding to the second portion 22 (the low-density portion 22A) as a starting point. As a result, the second molded body S4 having high quality can be easily obtained.

Second Embodiment

FIG. 7 is a sectional view of a laminate generated by a molded body producing apparatus according to a second embodiment of the present disclosure.

Hereinafter, a second embodiment of a method for producing a molded body and a molded body producing apparatus according to the present disclosure will be described with reference to FIG. 7, and only differences from the above embodiment will be described.

As shown in FIG. 7, in the present embodiment, the laminate S21 has two accumulated sheets S2. Hereinafter, a lower accumulated sheet S2 is referred to as an “accumulated sheet SA (first accumulated material)”, and an upper accumulated sheet S2 is referred to as an “accumulated sheet SB (second accumulated material)”. Further, in the bending step, it is assumed that the accumulated sheet SA is bent such that the accumulated sheet SA is located on an outer side and the accumulated sheet SB is located on an inner side.

As shown in FIG. 7, a length L1 of the second portion 22 of the accumulated sheet SA in the moving direction of the mesh belt 12 is larger than a length L2 of the second portion 22 of the accumulated sheet SB in the moving direction of the mesh belt 12. That is, in the accumulation step, the moving speed of the mesh belt 12 is adjusted such that the length L1 of the second portion 22 of the accumulated sheet SA in the moving direction of the mesh belt 12 is larger than the length L2 of the second portion 22 of the accumulated sheet SB in the moving direction of the mesh belt 12. By molding such a laminate S21, in the first molded body S3, when adjacent low-density portions 22A are compared, a low-density portion 22A on the upper side is shorter, and a low-density portion 22A on the lower side is longer.

In the bending step, when the first molded body S3 is bent such that the accumulated sheet SB is located on an inner side, a region to be bent or curved of the outer accumulated sheet SA is longer than that of the inner accumulated sheet SB. By taking the above difference into account and making the length L1 of the second portion 22 in the accumulated sheet SA longer than the length L2 of the second portion 22 in the accumulated sheet SB, the low-density portion 22A as described above is formed, and defects such as separation and positional deviation of the accumulated sheet SA and the accumulated sheet SB due to the above bending or curving can be prevented or suppressed. Therefore, the quality of the second molded body S4 can be more effectively improved.

In this way, in any two of the accumulated sheets S2 having the accumulated material M2 of the laminate S21, when bent in the bending step, the accumulated sheet S2 located outside is defined as the accumulated sheet SA as a first accumulated material, and the accumulated sheet S2 located inside is defined as the accumulated sheet SB as a second accumulated material, in the accumulation step, the moving speed of the mesh belt 12 is adjusted such that the length L1 of the second portion 22 in the transport direction of the mesh belt 12 in the accumulated sheet SA is longer than the length L2 of the second portion 22 in the transport direction of the mesh belt 12 in the accumulated sheet SB. Accordingly, in the bending step, defects such as separation and positional deviation of the accumulated sheet SA and the accumulated sheet SB can be prevented or suppressed. Therefore, the quality of the second molded body S4 can be more effectively improved.

In the present embodiment, the configuration in which the laminate S21 includes two accumulated sheets S2 has been described. However, the present disclosure is not limited thereto, and the laminate S21 may include three or more accumulated sheets S2. In this case, when attention is paid to any two accumulated sheets S2, if these satisfy the configuration of the present embodiment, the above-described effect can be obtained.

The length L1 is not particularly limited, but is, for example, preferably 7 mm or more and 70 mm or less, and more preferably 15 mm or more and 45 mm or less. Accordingly, it is possible to more easily and accurately perform the bending while more effectively preventing or suppressing the above-described defects.

The length L2 is not particularly limited, but is, for example, preferably 5 mm or more and 50 mm or less, and more preferably 10 mm or more and 35 mm or less. Accordingly, it is possible to more easily and accurately perform the bending while more effectively preventing or suppressing the above-described defects.

A ratio L2/L1 of the length L1 (mm) to the length L2 (mm) is not particularly limited, but is preferably 0.1 or more and 0.9 or less, and more preferably 0.2 or more and 0.8 or less. Accordingly, it is possible to more easily and accurately perform the bending while more effectively preventing or suppressing the above-described defects.

Third Embodiment

FIG. 8 is a sectional view of a laminate generated by a molded body producing apparatus according to a third embodiment of the present disclosure.

Hereinafter, a third embodiment of a method for producing a molded body and a molded body producing apparatus according to the present disclosure will be described with reference to FIG. 8, and only differences from the above embodiment will be described.

As shown in FIG. 8, the minimum thickness T₁ of the second portion 22 in the accumulated sheet SA is larger than the minimum thickness T₂ of the second portions 22 in the accumulated sheet SB. That is, the average thickness of the flat portion 221 in the accumulated sheet SA is larger than the average thickness of the flat portion 221 in the accumulated sheet SB. In the present embodiment, although not shown, the above-described accumulated sheet SA and accumulated sheet SB can be obtained by adjusting the moving speed of the mesh belt 12 in the accumulation step such that the minimum thickness T₁ of the second portion 22 of the accumulated sheet SA is larger than the minimum thickness T₂ of the second portion 22 of the accumulated sheet SB. By molding such a laminate S21, in the first molded body S3, when adjacent low-density portions 22A are compared, a low-density portion 22A on the upper side has a lower density of the material M1, and a low-density portion 22A on the lower side has a higher density of the material M1.

In the bending step, when bent such that the accumulated sheet SB is located on the inner side, a larger tension acts on the accumulated sheet SA on the outer side than on the accumulated sheet SB on the inner side. Therefore, the second portion 22 of the accumulated sheet SA is more likely to break than the second portion 22 of the accumulated sheet SB. In view of this, by setting the minimum thickness T₁ of the second portion 22 in the accumulated sheet SA to be larger than the minimum thickness T₂ of the second portion 22 in the accumulated sheet SB, the low-density portion 22A as described above is formed, and the breakage of the low-density portion 22A in the accumulated sheet SA can be more effectively prevented or suppressed. Therefore, the quality of the second molded body S4 can be more effectively improved, and the durability and yield of the second molded body S4 can be further improved.

In this way, in any two of the accumulated sheets S2 having the accumulated material M2 of the laminate S21, when bent in the bending step, the accumulated sheet S2 located outside is defined as the accumulated sheet SA as a first accumulated material, and the accumulated sheet S2 located inside is defined as the accumulated sheet SB as a second accumulated material, in the accumulation step, the moving speed of the mesh belt 12 is adjusted such that the thickness T₁ of the second portion 22 in the accumulated sheet SA is larger than the thickness T₂ of the second portion 22 in the accumulated sheet SB. Accordingly, in the bending step, the breakage of the accumulated sheet SA can be more effectively prevented or suppressed. Therefore, the quality of the second molded body S4 can be more effectively improved, and the durability and yield of the second molded body S4 can be further improved.

A ratio ρ_SB22/ρ_SA22 of the density ρ_SA22 (g/cm³) of the low-density portion 22A of the accumulated sheets SA in the first molded body S3 to the density ρ_SB22 (g/cm³) of the low-density portion 22A of the accumulated sheet SB in the first molded body S3 is not particularly limited, and is, for example, preferably 0.2 or more and 0.8 or less, and more preferably 0.3 or more and 0.7 or less. Accordingly, the breakage of the low-density portion 22A in the accumulated sheet SA can be more effectively prevented or suppressed. Therefore, the quality of the second molded body S4 can be more effectively improved, and the durability and yield of the second molded body S4 can be further improved.

Although the method for producing a molded body and the molded body producing apparatus of the present disclosure in each of the shown embodiments are described, but the present disclosure is not limited to these, and each section and each step constituting the method for producing a molded body and the molded body producing apparatus of the present disclosure may be replaced with any structure or step capable of exhibiting the same function. In addition, the method for producing a molded body and the molded body producing apparatus of the present disclosure may be added with any additional components and steps. In addition, the method for producing a molded body and the molded body producing apparatus of the present disclosure may be a combination of the features of the respective embodiments.

In particular, by combining the second embodiment and the third embodiment, defects such as separation and positional deviation of the accumulated sheet SA and the accumulated sheet SB in the bending step can be prevented or suppressed, and the breakage of the accumulated sheet SA can be more effectively prevented or suppressed. Therefore, the quality, durability, and yield of the second molded body S4 can be more effectively improved.

Further, in each of the embodiments described above, the configuration in which the accumulated sheets S2 are formed into the laminate S21 and then molded is described, but the present disclosure is not limited thereto, and a configuration in which the accumulated sheets S2 are molded and then stacked to form a laminate may be adopted. That is, a laminating step may be performed after the molding step.

Further, the present disclosure is not limited to controlling the thickness of the accumulated sheet S2 by the moving speed of the mesh belt 12 and the supply speed of the sheet S, and the thickness of the accumulated sheet S2 may be controlled by other methods to form thick portions and thin portions in the accumulated sheet S2. For example, the material M1 including fibers supplied to the dispersing section 11 may be supplied in a large amount in a portion to be thickened, and may be supplied in a small amount in a portion to be thinned. In addition, after being accumulated on the accumulated sheet S2 with a uniform thickness, the fibers in a portion to be thinned may be removed from the accumulated sheet S2.